Roller ski

ABSTRACT

The invention relates to a roller ski which is employed amongst other things for training in classic cross-country skiing during the summer. The object of this roller ski is to achieve a pressure-dependent grip when a kick is generated, with the result that more pressure on the ski from the foot provides better grip. This is in order to simulate skiing on snow, where in classic style pressure has to be placed on the ski during the kick in order to obtain grip on the middle of the ski. The invention is based on a common principle. Roller systems with free roll both forwards and backwards are combined with roller systems with one-way roll, in such a manner that when the pressure on the roller ski from the skier increases, the roller system(s) with one-way roll will be activated to an increasing extent as the pressure on the ski increases, with the result that the ski obtains grip thereby enabling a kick to be generated. The grip is obtained without any risk of the ski jerking in the event of unexpected pressure from a rough surface. Without extra pressure the roller ski will be liable to back-sliding just like a classic cross-country ski with grip wax under the middle and glide wax at the front and rear.

The present invention relates to a roller ski 100 comprising a wheel system which provides a pressure-dependent resistance to rearward roll.

Roller skis are employed by athletes and leisure skiers in order to train for cross-country skiing and various cross-country techniques, such as classic and skating, during the summer. A roller ski of this kind will then usually comprise two wheels, where the wheels are arranged at opposite ends of an elongated, ski-like element 4, together with a ski binding 19 which is designed to receive a ski boot, so that the user's foot is secured to the roller ski. The roller skis may furthermore be equipped with braking devices or the like, thereby enabling the user to slow down his speed when it becomes too great, or when dangerous situations arise during use of the roller ski.

Most of today's roller skis intended for training in classic style have wheels with a so-called one-way roll, i.e. they roll forwards and always lock rearward motion regardless of the pressure applied to the ski. This means that with current roller skis it is impossible to train for classic cross-country skiing with correct technique while simultaneously using a propulsion technique corresponding to that in classic cross-country skiing.

US 2008/0030014 A1 relates to a roller ski in which two freely-rolling wheels and an intermediate wheel with one-way roll are employed. The intermediate wheel is then arranged above ground level, i.e. not in contact with the ground when the roller ski is unloaded, and when a certain pressure is applied, the intermediate wheel comes into contact with the ground, in order thereby to provide the desired friction during a back kick. This solves the problem by providing a rearward kick, but the solution requires the use of at least three wheels. Furthermore, there is much discussion in the publication concerning ordinary brakes against one of the wheels which are mounted at the front or the rear of the roller ski, and known methods are further described for achieving a flexible roller ski in order to obtain pressure-dependence in the braking.

One of the objects of the roller ski according to the present invention is to provide a roller ski with a pressure-dependent rearward roll resistance, in which two wheels are sufficient, whereas three wheels are employed in the prior art. In addition it is extremely important that the brakes should only function in the rearward direction and on no account prevent almost free forward roll, since, for example in the event of compression in a dip, the risk would then arise of the roller skis braking, thereby causing a fall. An important point for many of the design variants in US 2008/0030014 A1 is that the brakes cause undesirable braking where there are irregularities in the surface when only using two wheels and in addition a device has to be employed which brakes one or both wheels as a function of pressure on the roller ski. This shows clearly that they have not seen the possibilities of implementing one-way roll with the use of only two wheels against the surface in the ways described by means of the roller ski according to the present invention.

The present invention relates to a roller ski comprising a wheel system which provides a pressure-dependent rearward roll resistance, in order thereby to simulate how a ski on snow behaves during skiing with classic style, where pressure has to be applied to the ski in the back kick in order to achieve grip in the middle of the ski, since the cross-country ski is provided with a camber and in addition glide wax is applied in a front and rear area of the cross-country ski, with the result that the cross-country ski has a minimum of grip when the central portion of the cross-country ski is not in contact with the surface.

The present invention is based on a common principle. A roller system with almost free roll both forwards and backwards when the roller ski is subjected to little or no pressure is combined and integrated with a system which provides pressure-dependent one-way roll, in such a manner that when the pressure on the roller ski from the skier increases, the roller system(s) with one-way roll will be activated to an increasing extent as the pressure on the roller ski increases, thereby causing the roller ski to obtain a grip so that a kick can be implemented. Without extra pressure the roller ski will be liable to slide backwards just like a ski with grip wax underneath the middle when it is not given enough pressure in the back kick.

According to the present invention the roller system with free roll 2 (or freely-rolling system) should be understood to be a system which permits free rotation both forwards and backwards in the roller ski's normal direction of travel when the ski is without pressure. In a similar manner a roller system with pressure-dependent one-way roll (or one-way roll system) according to the present invention should be understood to be a system which only permits rotation forwards in the roller ski's normal direction of travel, with the result that a wheel with a roller system with pressure-dependent one-way roll 22 may be an integrated combination of free roll 2 and one-way roll 1. Furthermore, free roll wheel 27 should be understood to be a wheel which can rotate both ways, regardless of the pressure load, while a roller system with pressure-dependent one-way roll should be understood to be a wheel which, when the pressure load is increased, provides increasing resistance to rearward roll.

Roller system 26 comprises wheels with axle 8 which without pressure roll freely both ways 2 and are equipped with one-way ratchets 1, 24, with the result that when this axle is pressed against a brake 10 consisting of oppositely directed ratchets 23 or 25, the axle and thereby the wheel is locked in a rearward direction of rotation, while the wheel can continue to roll forwards.

Basically, the use might be envisaged of a simpler system with a free roll wheel 27 combined with a pressure-activated brake. This would function adequately much of the time, but the problem is that when skiing over or on dips, or down in dips, thereby inadvertently subjecting a roller ski to a higher pressure, a roller ski of this kind will be braked, which can easily result in a fall. The invention therefore prescribes instead that in the event of increased pressure, one or more roller systems with pressure-dependent one-way roll come into operation, thereby permitting the roller ski to continue to roll freely forwards, but giving it pressure-dependent rearward roll resistance, thus giving force to the kick if the kick is combined with pressure increase on the roller ski concerned. The present invention will therefore provide the desired pressure-dependent grip for the kick, while simultaneously preventing the roller ski from braking suddenly when subjected to pressure.

A ski for classic cross-country skiing has so-called grip zones under the shoe. The invention does not place grip under the middle of the roller ski, since this may be impractical for the roller systems employed. The primary aim is to obtain pressure-dependent grip and not where this grip is provided on the roller ski. Preferred combinations of wheels with free-roll and wheels with pressure-dependent one-way roll may have pressure-dependent one-way roll only at the rear or only at the front of the roller ski, or both at the front and the rear. The invention does not involve the use of a third wheel with one-way roll 6 placed in line with or in series with two freely rolling wheels, so that the third wheel is activated against the ground when the roller ski is subjected to pressure.

The roller ski according to the present invention comprises at least one wheel system with pressure-dependent one-way roll.

The roller ski according to the present invention will now be described by means of some embodiments. The common feature of most of the embodiments is that when the foot presses on a profile under the ski boot, the pressure will be transferred to the roller systems, at least one of which has a spring suspension, with the result that the freely rolling system is pressed upwards, thereby activating the system which restricts rearward roll. However, a hydraulic/pneumatic system is also described, where the pressure increase activates one or more brakes on the freely rolling system, without it having a spring suspension.

A roller ski will often be equipped with an adjustable roll resistance on the wheels which have free roll. This has two advantages: it permits better adjustment of speed when training on flat roads, and the brake can be adjusted in downhill slopes in order to avoid reaching a dangerously high speed. An adjustable fixed brake of this kind may also be adapted to suit a wheel with pressure-dependent one-way roll if so desired.

The use of three wheels obviously results in a heavier roller ski and a more expensive roller ski to produce, and this is avoided with the roller ski according to the present invention. However, the introduction of an extra roller system also adds a little extra weight to the roller ski as well as extra production costs. It will therefore be optimal to employ pressure-dependent roll resistance only at one point, either behind the foot or in front, but this may be combined if so desired. All embodiments of the systems illustrated placed behind the foot may also be placed in front of the foot, in which case one can choose whether to have only a roller system with free roll 27 (freely rolling wheel) behind the foot, or whether to have a roller system with one-way roll (pressure-dependent system) for grip there too.

Pressure-dependent resistance may be obtained by, for example, having the rear wheel 5 suspended in an axle 8 which rolls freely both ways, but where the rotation in this axle may be checked by a braking device, for example a brake, which increases the braking effect with increasing pressure on the roller ski. The rear wheel in turn is mounted in an additional bearing where the rotation is one-way 1 (rearward block), thereby enabling the rear wheel to always roll freely forwards, but in order to roll backwards the brake on the axle must be off, i.e. the pressure on the roller ski must be below a certain level. When the pressure increases, the axle's rotation is checked successively more with increasing pressure, with the result that the one-way roll in the rear wheel becomes effective. One embodiment may be where the axle which has to be braked has spring suspension 7, so that when under pressure it abuts against a braking device 10, thereby achieving an increasing braking effect when there is an increase in pressure. This is particularly relevant if the brake is internally integrated in the wheel. Alternatively, there may be a mechanism which presses down on the axle when there is increased pressure on the roller ski, or any other known method whatever may be employed for checking the axle's rotation. In principle it is all the same whether the freely rolling axle 8 which is braked is located inside the wheel with one-way roll or vice versa, but it must be ensured that the axle which rolls freely both ways is that which is braked.

Pressure-dependent resistance may also be achieved by having one wheel (or both wheels) with pressure-dependent one-way brake 26 equipped with an axle or cylinder which has ratchets 24 or notches which permit rotation one way but prevent rotation the other way. This axle or cylinder then has spring suspension 7, with the result that when pressure is applied it will be pressed against a brake element provided with corresponding notches or ratchets 23 or 25 which are oppositely directed. When a certain pressure is applied the wheel will then be locked against rotation this one way, i.e. rearwards, while it will continue to run almost freely in the forward direction, where only a certain frictional resistance will become manifest. In order to minimise this frictional resistance during forward rotation, this embodiment will preferably be made of a smooth, strong material. The roller ski will then behave very like a real ski with grip wax, with the roller ski according to the invention “jerking” slightly when inadvertently encountering compression in dips, just as with ordinary skis when landing with the waxed central portion in situations with extra compression.

This object is achieved with a roller ski comprising a wheel system as indicated in the following independent patent claim 1, where further features of the invention will become apparent from the dependent claims and the description below.

The present invention relates to a roller ski comprising a wheel system which provides a pressure-dependent resistance to rearward roll, in order thereby to simulate how a ski on snow behaves.

When the user's foot presses on the profile 4 under the ski boot, the pressure will be transferred to the freely-rolling roller systems 2, at least one of which has a spring suspension 7, with the result that when pressure is applied to the roller ski 100 the first freely-rolling, spring suspended roller system 2 will be moved upwards relative to a brake, so that increased pressure on the roller ski couples the braking system with free roll 2, and the rotation of the roller system with one-way roll 1 is thereby determined when the pressure becomes sufficiently great, and the roller ski has resistance to rearward roll, and thereby pressure-dependent grip when a kick is implemented.

In an embodiment of the roller ski according to the present invention a wheel 27 which is permitted to rotate both ways may be spring suspended 7, with the result that when the pressure on the roller ski is increased, this wheel is pressed up against an overlying wheel with one-way roll 1, 6, where, when the pressure is increased, the overlying wheel with pressure-dependent one-way roll brakes the rear wheel's rearward roll, but provides free forward roll regardless of pressure.

In order to achieve a pressure-dependent resistance with the roller ski, in a further embodiment of the present invention at least one wheel may be suspended in an axle which is permitted to rotate freely both ways (i.e. both forwards and backwards in the roller ski's direction of travel), where this axle can be braked by a brake device which transfers pressure on the roller ski to the brake, for example via a wire 16, and where the wheel is mounted relative to its axle 8 with a rearward block (one-way roll) 1, with the result that the wheel can always roll forwards, but is prevented from rotating backwards in this system, when sufficient pressure is applied, so that an increasing pressure on the roller ski successively brakes the axle, thereby providing increased resistance to rearward roll.

In another preferred embodiment of the present invention at least one wheel may be suspended in the ski-like profile, where the wheel comprises a roller system 26 with a spring-mounted axle which without pressure is permitted to roll freely both ways, where the axle is equipped with one-way ratchets 24, thereby causing rotation to be checked when it is pressed against a one-way brake with oppositely directed one-way ratchets 23 or 25, with the result that under pressure the roller system only permits one-way rotation.

The above-described embodiments of the present invention comprise the use of ball bearings etc., but it should be understood that any technology whatever for suspension of rotating systems may be employed, where a person skilled in the art will know how this should be achieved. The known technology for roller systems with one-way roll normally has ball bearings which only permit one direction of rotation, these being employed in wheels 6 with one-way roll.

Several non-limiting embodiments of the present invention will now be described with reference to the accompanying drawings, in which

FIG. 1 illustrates a roller ski with a wheel system 22 for pressure-dependent resistance to rearward roll according to a first embodiment of the present invention, viewed from the side, in cross section from the side and from above,

FIGS. 2A-2B illustrate details of a wheel system 26 in a second embodiment of the roller ski according to the present invention,

FIGS. 3A-3B illustrate details of a wheel 26 with integrated pressure-dependent brake inside the wheel according to the present invention,

FIGS. 4A-4D illustrate details 23, 24, 25 of a wheel system 26 for the roller ski according to FIGS. 2 and 3,

FIGS. 5A-5B illustrate an embodiment of the roller ski according to the present invention, viewed from the side and from above,

FIG. 6 illustrates details of a wheel system of yet another embodiment of the roller ski with wire brake 16 according to the present invention,

FIGS. 7A-7B illustrate a wheel system 22 which can be integrated in the roller ski according to the present invention, viewed from the side and in cross section, and

FIGS. 8A-8B illustrates another wheel 22 with integrated pressure-dependent brake inside the wheel according to the present invention, viewed from the side and in cross section.

In the figures the different systems' direction of rotation may be indicated by arrows, where a double arrow indicates that a system is freely rolling (can rotate in both directions, both forwards and backwards), while a single arrow indicates that a system is pressure-dependent one-way (i.e. can only rotate in one direction). The single arrows further indicate which way the wheels rotate when the roller ski is used (in the roller ski's normal forward “direction of travel”), except for in FIG. 5.

FIG. 1 illustrates a first embodiment of a roller ski 100 according to the present invention, where the roller ski 100 comprises a front wheel 3 and a rear wheel 5, which two wheels 3, 5 are connected by a profile 4. On the profile 4 a binding 18 is mounted, to which a ski boot (not shown) is intended to be connected, and a binding profile 19, where the binding 18 and the binding profile 19 may be a unit, or also be composed of two separate units. The front wheel 3 and the rear wheel 5 are equipped with a roller system with pressure-dependent one-way roll 22. The front and rear wheels 3, 5 are connected to the profile 4 by means of a mounting device 14, to which mounting device 14 a shield 102 is also connected.

The roller 100 ski further comprises wheels with a freely-rolling axle 8 which can be braked on each side, and the axle 8 is located on the outside of a pressure-dependent one-way roll axle 1 which always ensures free forward roll but is locked rearwards in a one-way bearing. A spring 7, which in other figures is often illustrated directly on the wheels' 3, 5 axle, is mounted in FIG. 1 in the wheel's mounting device 14 inside the profile 4, and springs 12 are mounted in the profile 4 so that the wheel's mounting bracket 14 constitutes a spring arm.

Another adaption is for an overlying brake element 10 to be mounted at an adjustable angle slantingly in towards the profile 4, where the angle relative to a horizontal plane may typically vary between 10 and 45 degrees. This will provide a slight increase in brake pressure when contact is made between brake element 10 and a cylinder or axle 13.

The roller ski 100 is further illustrated with an adjusting device 9, thereby enabling the spring(s) 12 to be adjusted in order to obtain the desired pressure-dependent braking effect on the axle 8.

FIG. 2A illustrates a system for pressure-dependent one-way roll 26 which may be located at the rear (and/or the front) of a roller ski according to the present invention, viewed here in cross section from behind. The wheel has an axle 8 which is suspended in ball bearings 11 and permits free rotation of the axle 8 in both directions (clockwise and anticlockwise). The axle 8 is spring-mounted relative to the roller ski 100, with the result that when the pressure on the roller ski 100 exceeds a certain level, the axle's 8 external cylinder (enlarged axle) 24 with one-way ratchets 24A, 24B is pressed against the brake element 23, 25 (a different brake element is indicated employed on each side of the wheel, even though in principle either brake element 23 or brake element 25 will be employed on both sides of the wheel which is equipped with oppositely directed one-way ratchets 23A, 25A), thereby causing the wheels to be locked against rotation in one direction when a certain pressure is applied. In some embodiments a certain resistance will also arise to forward roll when pressure is applied to the system, but this resistance can be restricted by the choice of smooth materials and correct geometry on cylinder 24 and brake 23. If brake element 25 is used with spring ratchet 25A, almost no forward roll resistance is to be expected. The pressure required to obtain pressure-dependent one-way roll must be adjustable, preferably both by being able to replace elements in the roller ski which influence the resilience (for example springs with different stiffness) and/or by using a device for pressure adjustment of the roller ski (for example an adjustable distance or moment). One possible example of pressure adjustment is illustrated in FIG. 1.

FIG. 2B illustrates a cross section of a wheel and suspension system 26 viewed from the side. The point here is that a practical spring device 7 exists which ensures that the rear part of the profile 4 provides an attachment for a glider pocket G with spring resistance in which the ball bearing 11 holding the axle 8 will be able to be pressed upwards. In the glider pocket G one or more springs 12 will then be mounted, which spring or springs will be compressed when the ball bearing 11 and the axle 8 move in the glider pocket G when pressure is applied.

FIG. 3B also illustrates a possible example of a vertical glider pocket G, which according to the principle in FIG. 2 will be placed on the outside of the actual wheel. However, instead of glider pocket G the same arrangement as in FIG. 1 with a spring arm may also be employed.

FIG. 3A is a cross sectional view of a wheel with pressure-dependent one-way roll roller system 26 integrated inside the wheel, where the principle from FIG. 2 is integrated in its entirety as a part of the wheel, so that it is attached to the profile 4 in such a manner that there is no rotation in the attachment point, and no spring suspension outside the wheel. The wheel has a rotating axle 8 internally between two ball bearings 11 with free roll 2, where the actual ball bearing 11 is non-rotatingly suspended in an extension of the wheel's attachment to the profile 4, but the whole ball bearing 11 may be sprung vertically. When the wheel 26 is subjected to pressure, the axle 8 with its cylinder 24 with one-way ratchet will be pushed upwards and the rotation is stopped in a direction against the brake 23 or 25 which has oppositely directed ratchets. When the cylinder 24 on the axle 8 is securely locked against the brake 23, 25, the wheel can only roll forwards round the axle 8. The right and left sides of the wheel are shown in different embodiments, only in order to illustrate different arrangements and to show that symmetry is not a requirement, but in practice a symmetrical arrangement is used in one and the same wheel. Springs 7 are shown both above and below the axle 8, and slightly different resistance may be employed in the spring system above and below the axle 8, with the result that if the wheel mount is rotated 180 degrees, a different pressure resistance is obtained before the one-way roll is activated. The same result may be achieved by using slightly different spacing between axle and brake above and below the axle.

FIG. 3B illustrates a cross section through the vertical spring suspension for the ball bearing 11 in which the axle 8 rotates.

FIGS. 4A-4D illustrate different possible variants of one-way ratchets on the axle or cylinder 24 and associated brake element 23 viewed from the side and slightly enlarged. The object here is to obtain a system which provides the least possible braking effect for forward roll and the greatest possible effect for rearward roll when the system with the axle or the cylinder 24 and the brake element 23 are brought into contact with one another (pressed together). Low friction is achieved in the forward direction, particularly with the use of spring ratchets 25. In the figures the different directions of rotation are indicated by arrows, where a double arrow indicates a rotation in both directions without pressure, while a single arrow indicates only one direction of rotation when cylinder 24 and brake element 23 or brake element 25 are pressed together.

In FIG. 4A the brake element 23 is provided with a number of ratchets 23A which will permit the axle or the cylinder 24 to rotate one way (e.g. in the one-way arrow's direction, i.e. clockwise), but will prevent the axle or the cylinder 24 from rotating in an opposite direction. The axle or the cylinder 24 will then be provided with corresponding notches 24A, with the result that, when the brake element 23 and the axle or cylinder 24 are brought into contact, a certain pressure on the roller ski will cause a full stop to be obtained in a direction of rotation.

FIG. 4B illustrates another embodiment of the brake element 23 and the axle or the cylinder 24, where the brake element 23 is now provided with notches 23B, while the axle or the cylinder 24 is provided with corresponding ratchets 24B.

FIG. 4C illustrates another embodiment of a brake element 25, where the brake element 25 is now provided with a number of spring ratchets 25A. The axle or the cylinder 24 may also be provided with corresponding notches or ratchets as illustrated in FIG. 4A or 4B.

FIG. 4D illustrates yet another embodiment of the brake element 23 and the axle or the cylinder 24, where ratchets and notches are of a different shape from those illustrated in FIGS. 4A to 4C.

FIG. 5A illustrates an indirect method for implementing one-way roll by means of pressure. The front wheel 3 is freely rolling and the rear wheel 5 is freely rolling 27 and spring mounted 7, and over the freely rolling rear wheel 5 a one-way rolling system 1 is located. When the freely rolling wheel 5 is pressed up towards the one-way rolling wheel 1, 6, the friction between these two wheels 27, 6 will cause wheel 27 to also become gradually more one-way rolling with increasing pressure on the ski. Note that the one-way roll in wheel 6 here is the opposite way to previously illustrated examples, since it acts indirectly via wheel 27.

FIG. 5B illustrates the roller ski viewed from above.

FIG. 6 illustrates a cross section of a wheel system 22 with one-way roll internally 1 and an axle 8 which rotates freely 2 in a ball bearing 11, where this axle 8 has a brake disc which is braked via a wire 16 to a brake 10 where the wire is tightened when pressure is applied to the roller ski from the foot. This may be accomplished in many ways. One way is to have the wheel 6 spring-suspended with the wire located in a fixed extension of the roller ski. When the wheel 6 goes up, the wire 16 is tightened and the brake 10 is activated. Another way may be with a device which absorbs the pressure in the shoe attachment (not shown), thereby pulling the wire.

FIG. 7A illustrates an integrated wheel 22 which can be placed at the rear (and/or in front) of a roller ski, viewed here in cross section from behind. The wheel has an axle 8 which has a one-way roll 1, with the result that when the axle 8 is securely locked, the wheel can only roll forwards round the axle. The axle is spring-suspended externally in a ball bearing 11 with free roll 2 both ways. When the roller ski comes under pressure, the whole of the external ball bearing 11 will be pressed upwards against the resistance from a spring and the small wheel 13 which is fixed externally on the axle 8 is pressed up towards a fixed rigid brake 10. The more pressure there is on the wheel, the more the free rotation 2 in the axle 8 will thereby be braked, whereby the one-way roll function 1 is gradually coupled inside the wheel, and the rearward roll resistance is thereby increased with increasing pressure on the ski.

FIG. 7B illustrates the integrated wheel 6 viewed from the side. The rear part of the profile 4 is illustrated in a rough outline—it has spring resistance against which the ball bearing 11 holding the axle 8 should be able to be upwardly pressed against.

FIG. 8A illustrates a wholly-integrated wheel 22 viewed in cross section from behind, where the principle in FIG. 7 is integrated in its entirety as a part of the wheel, whereby the latter is attached to the profile 4 in such a manner that there is no rotation in the mounting point, nor is there any spring suspension outside the wheel. The wheel has a rotating axle 8 internally between two ball bearings 11 with free roll 2, where the actual ball bearing is non-rotatingly suspended in an extension of the wheel's attachment to the profile 4, but the whole ball bearing may be vertically sprung. When the wheel is subjected to pressure, the axle 8 will be pressed upwards and the rotation checked against the brake 10. The actual wheel is rigidly fixed to the axle 8 via a one-way rotating system 1. When the axle 8 is securely locked against the brake 10, the wheel can only roll forwards round the axle 8 via the one-way roller system 1. The right and left sides of the wheel are shown in different versions merely to illustrate different arrangements and the fact that symmetry is not a requirement, but in practice a symmetrical arrangement is usually employed in one and the same wheel.

FIG. 8B illustrates a cross section from the side through the vertical spring suspension for the ball bearing 11 in which the axle 8 freely rotates.

There has been talk throughout of spring systems, but there are far too many of these on the market to describe this in more than a superficial manner. The use of any known spring system may be envisaged implemented in this connection.

When we say here that a wheel system is pressed upwards relative to another, it often means that it is the other system which is pressed down, in which case it is only a matter of what constitutes the fixed point.

Wheels with one-way roll are known from today's roller skis, and the technology exists in many variants which we shall not describe in greater detail here, but only present a schematic illustration of a type of one-way roll. The same applies for the one-way brake in FIGS. 2 and 3, where we intend to use a variant of known technology, with the result that it is the combination of the spring suspension applied to roller skis which is novel.

These were some outlines of variants of embodiments of the principles of the invention, where in practice many other variants thereof may be chosen.

The invention has now been explained by means of several embodiments. Only elements connected with the invention have been described and a person skilled in the art will understand that with the present roller ski, spring systems not illustrated here may be employed in order to achieve the desired braking effect.

REFERENCE TERMS EMPLOYED IN THE FIGURES

1. Device/system with one-way rotation

2. Device/system with free rotation both ways

3. Front wheel

4. Profile connecting front wheel and rear wheel

5. Rear wheel

6. Wheel with one-way rotation

7. Spring (yielding) suspension

8. Axle with free rotation

9. Adjustment of pressure

10. Brake

11. Ball bearings or the like suited for axle mounting

12. Elastic spring

13. Small auxiliary wheel

14. The wheel's mounting arrangement

15. Line for hydraulic fluid/air

16. Wire

17. Ski boot

18. Binding attachment for the shoe

19. Binding profile under boot

20. The ground, usually asphalt

21. Tyre material

22. System of wheel and suspension, where both system 1 and system 2 are integrated

23. One-way brake element with one-way ratchets

23A. Ratchets in brake element

24. Cylinder (wheel) axle with one-way ratchets

24A. Notches in axle or cylinder 24

25. One-way brake element with spring ratchets

25A. Spring ratchets in brake element 25

26. System of wheel and suspension, where both system 24 and system 23/25 are integrated into a pressure-dependent one-way roller system

27. Wheel with free roll both ways (FIG. 5)

100. Roller ski

101. Notch

102. Protective profile

103. Reinforced portion

G. Glider pocket

S. Shield 

1.-14. (canceled)
 15. A roller ski with a central portion where the shoe is attached to the profile connecting the wheels, where the different wheels are so designed that when the roller ski is without pressure it will roll fairly freely both ways, and when pressure is applied to the roller ski, the rearward roll resistance will increase with increasing pressure from the roller ski against the surface, this being accomplished by a pressure-dependent brake locking the rearward roll direction, while the forward roll direction continues to roll with little or no braking when the roller ski is subjected to pressure, wherein pressure-dependent resistance against rearward roll is achieved by combining two roller systems, where a first roller system has free forward roll and resistance to rearward roll, the first roller system comprising a brake element and one or more springs arranged in a glider pocket, and a second roller system has free roll both ways, the second roller system comprising a wheel an axle and auxiliary wheel or cylinder arranged on the axle, the first and second roller systems being arranged in such a manner relative to each other that without pressure on the roller ski, the second roller system is active, but as the pressure increases, the relative influence of the first roller system also increases since the second roller system is braked when pressure on the roller ski increases.
 16. A roller ski according to claim 15, wherein when the foot presses on the profile under the shoe, the pressure will be transferred to the first and second roller systems, with the result that when pressure is applied to the roller ski, the second roller system will be moved upwards relative to the first roller system providing one-way roll, so that increased pressure on the roller ski engages the first roller system, thereby providing pressure-dependent grip when a kick is implemented.
 17. A roller ski according to claim 15, wherein the roller ski at all times has only 2 wheels against the surface, one wheel in front of the shoe and one wheel behind the shoe.
 18. A roller ski according to claim 15, wherein pressure-dependent resistance against rearward roll is achieved by an axle which rolls freely both ways being equipped with one-way ratchets, with the result that when this axle is pressed against a brake consisting of oppositely-directed ratchets, the axle is locked and thereby the wheel in a rearward direction of rotation, while the wheel rolls forwards with only a slight braking effect in this direction, even when the pressure on the ski is so great that there is little or no rearward rotation.
 19. A roller ski according to claim 15, wherein the axle is equipped with one or more cylinders with a larger radius than the axle, and braking surface or ratchets are placed on the cylinder, with the result that the braking surface is greater than only the axle, and opposite brakes are adapted to the cylinder.
 20. A roller ski according to claim 15, wherein the wheel is suspended in an axle which rolls freely both ways, where this axle is braked by a brake device which transfers pressure on the ski to the brake via, e.g. a wire, and the wheel is mounted relative to its axle with a backward stop, thereby enabling the wheel to always roll freely forwards, but to be successively more prevented from rotating backwards in this system with increasing pressure on the ski.
 21. A roller ski according to claim 15, wherein the wheel is suspended in an axle which rolls freely both ways, where this axle is spring-suspended so that the axle's rotation will be checked when it is pressed up against a fixed brake, and the wheel is mounted relative to its axle with a backward stop, thereby enabling the wheel to always roll forwards, but to be successively more prevented from rotating backwards in this system with increasing pressure on the ski.
 22. A roller ski according to claim 15, wherein a wheel is securely suspended in the profile and that the wheel contains an integrated roller system with spring-suspended axle which without pressure rolls freely both ways, with the result that the axle's rotation will be checked when the axle or an auxiliary wheel is pressed up against a fixed brake, so that one-way rotation takes over.
 23. A roller ski according to claim 15, wherein a wheel which rolls freely both ways is spring-suspended so that when pressure is applied it is pressed up towards an overlying wheel which has one-way roll, with the result that when pressure is increased, the overlying wheel brakes the wheel's rearward roll, but provides free forward roll regardless of pressure.
 24. A roller ski according to claim 15, wherein the pressure required for braking the freely-rolling axle is transferred hydraulically or pneumatically to a brake device.
 25. A roller ski according to claim 15, wherein pressure-dependent resistance against rearward roll is assigned to the front wheel instead of the rear wheel.
 26. A roller ski according to claim 15, wherein it further comprises an adjustable, non-pressure-dependent roll resistance. 